Confirmed cardiac output on emergency medical services arrival as confounding by indication: an observational study of prehospital airway management in patients with out-of-hospital cardiac arrest

Association Between Advanced Airway Management With Adrenaline Injection and Prognosis in Adult Patients With Asystole Asphyxia Out-of-hospital Cardiac Arrest

BACKGROUND

The neurological prognosis of asphyxia is poor and the effect of advanced airway management (AAM) in the prehospital setting remains unclear. This study aimed to evaluate the association between AAM with adrenaline injection and prognosis in adult patients with asystole asphyxia out-of-hospital cardiac arrest (OHCA).

METHODS

This study assessed all-Japan Utstein cohort registry data between January 1, 2013 and December 31, 2019. We used propensity score matching analyses before logistic regression analysis to evaluate the effect of AAM on favorable neurological outcome.

RESULTS

There were 879,057 OHCA cases, including 70,299 cases of asphyxia OHCAs. We extracted the data of 13,642 cases provided with adrenaline injection by emergency medical service. We divided 7,945 asphyxia OHCA cases in asystole into 5,592 and 2,353 with and without AAM, respectively. After 1:1 propensity score matching, 2,338 asphyxia OHCA cases with AAM were matched with 2,338 cases without AAM. Favorable neurological outcome was not significantly different between the AAM and no AAM groups (adjusted odds ratio [OR] 1.1; 95% confidence interval [CI], 0.5-2.5). However, the return of spontaneous circulation (ROSC) (adjusted OR 1.7; 95% CI, 1.5-1.9) and 1-month survival (adjusted OR 1.5; 95% CI, 1.1-1.9) were improved in the AAM group.

CONCLUSION

AAM with adrenaline injection for patients with asphyxia OHCA in asystole was associated with improved ROSC and 1-month survival rate but showed no differences in neurologically favorable outcome. Further prospective studies may comprehensively evaluate the effect of AAM for patients with asphyxia.

Location of arrest and effect of prehospital advanced airway management after emergency medical service-witnessed out-of-hospital cardiac arrest: nationwide observational study

OBJECTIVES

To investigate the association of prehospital advanced airway management (AAM) on outcomes of emergency medical service (EMS)-witnessed out-of-hospital cardiac arrest (OHCA) according to the location of arrest.

METHODS

We evaluated a Korean national OHCA database from 2012 to 2016. Adults with EMS-witnessed, non-traumatic OHCA were included. Patients were categorised into four groups according to whether prehospital AAM was conducted (yes/no) and location of arrest ('at scene' or 'in the ambulance'). The primary outcome was discharge with good neurological recovery (cerebral performance category 1 or 2). Multivariable logistic regression analysis was conducted to evaluate the association between AAM and outcome according to the location of arrest.

RESULTS

Among 6620 cases, 1425 (21.5%) cases of arrest occurred 'at the scene', and 5195 (78.5%) cases of arrest occurred 'in an ambulance'. Prehospital AAM was performed in 272 (19.1%) OHCAs occurring 'at the scene' and 645 (12.4%) OHCAs occurring 'in an ambulance'. Patients with OHCA in the ambulance who had prehospital AAM showed the lowest good neurological recovery rate (6.0%) compared with OHCAs in the ambulance with no AAM (8.9%), OHCA at scene with AAM (10.7%) and OHCA at scene with no AAM (7.7%). For OHCAs occurring in the ambulance, the use of AAM had an adjusted OR of 0.67 (95% CI 0.45 to 0.98) for good neurological recovery.

CONCLUSION

Our data show no benefit of AAM in patients with EMS-witnessed OHCA. For patients with OHCA occurring in the ambulance, AAM was associated with worse clinical outcome.